Vehicles that emit less carbon dioxide, such as plugin hybrid vehicles and electric vehicles, are environment-friendly and have become popular. Such a vehicle is powered by a battery, and the body of the vehicle is provided with an inlet (charge inlet) used to charge the battery. A power plug of a charge cable provided in a charging facility is connectable to the inlet. When a power switch of the power plug is turned on, power is supplied through the charge cable to charge the battery. Japanese Laid-Open Patent Publication No. 9-161898 describes one example of such a power plug.